1. Field of the Invention
The present invention relates to cosmetic compositions useful for dry and/or sensitive and/or ageing skin.
2. Background Information
Skin is the largest organ of the human body, the condition in which the skin is contributes to a large extent to the well-being of humans. Human skin is exposed to an array of irritants such as UV-light, air pollution etc. In addition extensive sun-bathing or air-conditioning increases the rate of so called dry-skin conditions. In addition there is a trend in modern cosmetics to delay the normal ageing process of human skin, thereby providing a youthful/healthy appearance.
The aim of the invention was to provide a cosmetic composition which can be used on human skin, preferably to prevent dry skin and/or to help to maintain and/or improve moisture retention and/or to fight against the signs of ageing skin. The cosmetic composition should be highly effective, it should be easily applicable in a broad range of cosmetic formulations (e.g. W/O emulsions, O/W emulsions etc.) and it should preferably show little or no irritation on the skin. It has surprisingly been found that the cosmetic compositions according to the invention fulfil these requirements.
WO 2004/017901 describes cosmetic compositions comprising a Ca2+ salt, preferably as Calciumglycerophophate, which can be combined with an alpha-hydroxy acid for skin treatment. U.S. Pat. No. 5,296,476 describes cosmetic compositions comprising micronized calcium citrate in combination with salicylic acid for the treatment of acne. EP 0 588 498 describes calcium citrate in topical compositions for the protection against ultraviolet radiation. WO 2005/018596 describes antiperspirant compositions comprising aluminium-zirconium chlorohydrate antiperspirant salts in combination with a water soluble calcium salt. WO 2005/055927 describes the use of calcium salts for the treatment of acne, warts, rosacea, periodontitis and preventing of scar formation. WO 2006/000992 describes a composition for oral or topical applications, which comprises at least one microorganism in combination with a least on divalent inorganic cation, e.g. calcium citrate. JP 2791179 describes a cosmetic composition with good moisture retention which 1.0-30.0 wt. % at least one selected from a bivalent-trivalent metal salt of acid (e.g. calcium lactate) and a bivalent-trivalent metal hydroxide (e.g. aluminum hydroxide), 3.0-30 wt. % water-soluble salt of alginic acid, 3-20 wt. % oil component and 50-95 wt. powder. Cosmetic compositions comprising Calcium citrate are described in U.S. Pat. No. 2,719,811. The etiology of dry skin is complex, among many other factors skin lipids, such as ceramides are reported to be involved (Castiel-Higounec, M. Chopart, C. Ferraris. Huiles, corps gras et produis cosmétiques, 2004, 11, 401-6]. Topical application of skin lipids has been suggested as remedy (K. R. Feingold. Journal of Lipid Research, 2007, 48, 2531-46). Aged skin is reported to be characterized by altered drug permeability, increased susceptibility to irritant contact dermatitis and severe xerosis (Ghadially et al, 1995 J. Clin. Invest., 1995, 95, 2281-90) Supplying skin with endogenous lipids as well as topically applied anti-oxidants has been suggested to treat aged skin (J Thiele, C. O. Barland, R. Ghadially, P. M. Elias. Permeability and Antioxidant barriers in Aged Epidermis, Chap 7 in Skin Aging, B. Gilchrest and J. Krutmann Eds, Springer, 2006).
The increase of ceramidase in bacterial flora of patients suffering from atopic dermatitis is reported (Y Ohnishi et al. Clinical and Diagnostic Laboratory Immunology 1999, 6, 101-4). U.S. Pat. No. 5,851,782 describes D-erythro-2-(N-myristoylamino)-1-phenyl-1-propanol (D-e-MAPP) as ceramidase inhibitor and its use for the treatment of hyperproliferative diseases/disorders. WO 02/09687 discloses the use of N-Oleylethanolamine for the treatment of psoriasis.